OTHER FINANCIAL DATA (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Sales	$ 1,635.0	$ 1,872.4	$ 1,728.4	$ 1,710.3	$ 1,619.9	$ 1,554.9	$ 1,526.5	$ 1,567.1	$ 6,946.1	$ 6,268.4	$ 5,550.6
Cost of goods sold	1,391.0	1,441.7	1,460.7	1,528.7	1,400.2	1,349.3	1,407.9	1,397.5	5,822.1	5,554.9	4,944.5
Net income (loss)	$ 53.3	$ 195.1	$ 58.6	$ 20.9	$ 489.3	$ 52.7	$ (5.9)	$ 13.4	$ 327.9	$ 549.5	$ (3.9)
Earnings per Share, Basic [Abstract]
Basic net income (loss) per share (in dollars per share)	$ 0.32	$ 1.17	$ 0.35	$ 0.13	$ 2.93	$ 0.32	$ (0.04)	$ 0.08	$ 1.97	$ 3.31	$ (0.02)
Earnings per Share, Diluted [Abstract]
Diluted net income (loss) per share (in dollars per share)	0.32	1.16	0.35	0.12	2.89	0.31	(0.04)	0.08	1.95	3.26	$ (0.02)
Common dividends per share (in dollars per share)	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.80	$ 0.80